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DOE OSTI · 2204851

Godiva IV Burst Reproducibility and Diagnostic Testing

Goda, Joetta M.·Grove, Travis·Pierson, Bruce·Redhouse, Danielle·Weldon, Jr., Robert A.
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Abstract

Godiva IV is a fast burst critical assembly located at the Nation Criticality Experiment Research Center (NCERC) in the Nevada National Security Site (NNSS). It is constructed of approximately 65 kg of highly enriched uranium (HEU) fuel alloyed with 1.5% molybdenum for strength. The assembly can be operated at delayed critical or can be used to perform super-prompt critical bursts with temperature rises of up to 250 °C. Several projects with the objective of characterizing Go diva IV are ongoing including characterizations of its radiation emission and thermomechanics. One of the characterization projects is a study of the variability in the relative source emission (or fluence in absolute terms) between bursts that are nominally the same size. There is some inherent variation in the number of fissions, or "size" of the burst, even for bursts where the operators perform identical processes. The source of the variation can be attributed to several factors. The largest contributor is the precision with which the operators are able to determine delayed critical (DC). Operators find DC for every burst operation. The impact of being slightly above or below DC can change the super-prompt critical reactivity and therefore the source term. The temperature of the fuel is another factor. Establishing delayed critical prior to performing a burst act as a control of the bulk temperature coefficient of reactivity.

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21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTSDelayed Critical (DC)Godiva IVHighly Enriched Uranium (HEU)Integral ExperimentsNation Criticality Experiment Research Center (NCERC)Nevada National Security Site (NNSS)Nuclear Criticality Safety Program (NCSP)

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Goda, Joetta M., Grove, Travis, Pierson, Bruce, Redhouse, Danielle, Weldon, Jr., Robert A.. 2023-11-15. Godiva IV Burst Reproducibility and Diagnostic Testing. https://www.osti.gov/biblio/2204851

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